Generating function
$$U_{1314}(x, y) = \frac{\left(- 2 x \left(y + 1\right)^{3} - \sqrt{- 4 x \left(y + 1\right)^{3} + 1} + 1\right)^{3}}{8 x^{6} \left(y + 1\right)^{15}}$$
Explicit formula
$$T_{1314}(n, m, k) = \frac{3 k {\binom{3 k + 3 n}{m}} {\binom{6 k + 2 n}{n}}}{3 k + n}$$
Data table
1 3 3 1 0 0 0
6 36 9 12 9 36 6
27 243 972 2268 3402 3402 2268
11 132 726 242 5445 8712 10164
429 6435 45045 195195 585585 1288287 2147145
1638 29484 250614 1336608 501228 14034384 30407832
6188 129948 129948 823004 3703518 125919612 335785632
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